| Term | Definition |
|---|---|
| force | Any push or pull by one object on another |
| friction | A force that opposes the motion of one object moving past another |
| air resistance | A force that opposes the motion of objects moving though air |
| balanced forces | Forces that act together on an object without changing its motion |
| unbalanced force | forces that do not cancel each other out and that cause an object to change its motion |
